Glu-B1位点亚基色谱鉴定及7OE对面团强度的影响

准准确鉴定高分子量谷蛋白亚基（HMW-GS）及探讨其对面团特性的影响是小麦品质研究的重要内容。用聚丙烯酰胺凝胶电泳（SDS-PAGE）和反相高效液相色谱（RP-HPLC）对62份品种（系）的HMW-GS组成进行鉴定。结果表明，结合SDS-PAGE和RP-HPLC两种方法可以对Glu-B1位点，尤其是Glu-B1（7+8）进行有效鉴定。选用13份姊妹系为材料，使用RP-HPLC和凝胶色谱（SE-HPLC）方法，研究了Glu-B1al（7^OE+8*）以及贮藏蛋白组分含量对面团强度的影响。结果表明，Glu-B1al（7^OE+8*）可显著提高HWM-GS总量和面团强度，7OE可作为优质亚基用于强筋小麦育种。相关性分析表明，谷蛋白总量、HWM-GS、LMW-GS以及x-HMW含量与最大抗阻力呈1%显著正相关，相关系数分别为0.76、0.76、0.77和0.72。SDS-不溶性谷蛋白大聚体（UPP）占谷蛋白聚合体总量的百分比与揉面仪峰值时间、粉质仪形成时间和稳定时间以及最大抗阻呈1%或0.1%显著正相关，相关系数分别为0.77、0.90、0.89和0.87。醇溶蛋白与谷蛋白含量的比值与揉面仪峰值时间呈1%显著负相关，相关系数为－0.69；与粉质仪稳定时间和最大抗阻呈5%显著负相关，相关系数分别为－0.58和－0.64。HPLC可有效分离和量化HWM-GS，并作为小麦品质育种有效的辅助手段。     

抗赤霉病小麦地方品种的贮藏蛋白分析

采用A-PAGE和SDS-PAGE方法,对来自不同地方的23个抗赤霉病小麦地方品种的醇溶蛋白和谷蛋白亚基进行了分析。结果表明,在A-PAGE电泳分析中,23个供试品种具有23种不同的醇溶蛋白带型,共分离出39条相对迁移率不同的谱带,其中31条具有多态性,占86.8％,每份材料可电泳出14～23条带,存在着广泛的等位基因变异。在SDS-PAGE电泳分析中,出现了9种不同的高分子量谷蛋白亚基及6种亚基组合类型,优质亚基及亚基组合所占的比例较少,品质评分较低,其变幅为5～9分,平均为6.8分。     

小麦籽粒谷蛋白大聚合体粒度分布特征及对氮素的响应

为了给小麦品质改良提供依据,以强筋小麦品种藁城8901和弱筋小麦品种山农1391为材料,设置不同氮素水平,研究了籽粒谷蛋白大聚合体(GMP)颗粒粒径分布特征及对氮素水平的响应.结果表明,小麦籽粒GMP颗粒粒径范围为0.375～200 μm.GMP颗粒体积分布总体上呈双峰曲线变化,＜12 μm的GMP颗粒体积百分比为11.2％～45％,＞12 μm的GMP颗粒体积百分比为55.0％～88.8％.与弱筋小麦山农1391相比,强筋小麦藁城8901有较高比例的＞12 μm颗粒.GMP颗粒数目分布表现为单峰分布,＜4 μm和＜12 μm的颗粒数目百分比分别为97.5％～98.0％和99.9％,表明小麦GMP颗粒中绝大多数为＜4 μm的小颗粒.在施氮0～240 kg·hm-2范围内,随着施氮量的增加,＜12 μm颗粒体积百分比显著降低,12～90 μm、＞90 μm颗粒体积百分比增加,说明适量施氮能够显著提高GMP大、中颗粒比例.过量氮素不利于小麦籽粒谷蛋白大聚合体的形成.     

Glu-1位点缺失对小麦麦谷蛋白聚合体粒度分布及面团特性的影响

以Glu-1位点正常和部分缺失的小麦品系为材料,探讨HMW-GS和LMW-GS组成与谷蛋白聚合体粒度分布和面团特性的关系,为利用HMW-GS缺失系改良小麦品质提供理论依据。在20个供试硬白冬麦品系中,1个品系为Glu-A1位点缺失,5个品系为Glu-D1缺失,3个品系为Glu-A1和Glu-D1双缺失。所有品系的蛋白质含量皆较高(13.39%~14.12%),品系间无显著差异,缺失系与非缺失系间也无显著差异。Glu-1位点缺失显著降低了高分子量谷蛋白/低分子量谷蛋白比(HMW/LMW)、不溶性谷蛋白大聚体的含量和百分比。谷蛋白/醇溶蛋白比(GLU/GLI)在基因型间变幅较小,且在缺失系和非缺失系间无显著差异。Glu-1位点缺失显著降低了面团弹性,但显著提高了面团的延展性。部分Glu-1位点缺失系仍具有较高的面团强度和突出的延展性,谷蛋白聚合体粒度分布和面团特性受谷蛋白亚基组成和表达量的共同影响。研究结果表明,利用Glu-1位点亚基缺失可能是改善面筋延展性,提高食品加工品质的方法之一。     

Composition and Content of High-Molecular-Weight Glutenin Subunits and Their Effects on Wheat Quality

Sedimentation values, flour glutenin macropolymer (GMP) contents, composition and contents of high-molecular-weight (HMW) glutenin subunits (GS) of 233 flour samples were determined. Our data indicated that subunit 1 occurred more frequently at Glu-A1, subunit pair 7 + 8 at Glu- B1 and 2 + 12 at Glu-D1. The significant relationships between Glu-1 quality score and total HMW glutenin content, sedimentation value and GMP content suggested that the composition of HMW-GS affects wheat quality strongly. Moreover,the total content of HMW-GS was correlated with certain quality parameters more significantly. Relationship between subunit 5 + 10 content and breadmaking quality was better than others, but 2 + 12, 7 + 8, 7 + 9 and 4 + 12 also correlated with certain quality parameters significantly. The contents of total HMW-glutenin, x-type subunits and y-type subunits related with sedimentation value, flour GMP content, and Glu-1 quality score more strongly than that of individual subunit or subunit pair. The flour GMP content, with excellent correlation to sedimentation value, total contents of HMW glutenin, x- and y-type subunits and many other quality parameters, could be an ideal indicator of breadmaking quality at earlier generations for breeding purpose for its simple procedure and small scale.     

Allelic Variation of Glu-A1, Glu-B1 and Glu-D1 in Chinese Released Wheat Varieties in the Last 50 Years

The high-molecular-weight glutenin subunit (HMW-GS) components from about 85 varieties were fractionated by SDS-PAGE, including 22 corner stone breeding parents, 45 varieties taking important role in Chinese wheat production and 18 varieties with good bread making quality. The 22 corner stone breeding lines carry either null (c) or 1 (a) subunits on Glu-A1 loci. Five types are detected on Glu-B1, which are 7+8(b), 7+9 (c), 14+15 (h), 17+18 (i), 6+8 (d). 7+8 and 7+9 are the two major types. Six types have been detected on Glu-D1, which are 2 + 12 (a), 2 + 10 (e), 5 + 10 (d), 4+ 10 (j), 4 + 12 (c), 2 + 11 (g). 2 + 12 and 2 + 11 are the two major types. In the corner stone breeding lines, early premium from American carries 5 + 10, St2422/464 from Italy carries the 14 + 15. In addition, two relatively essential varieties, Mara and Alondra carry 5 + 10. In the 45 commercialized varieties, sowed more than 666 000 ha (10 million mu) annually, only Yangmai 5 conveys the 5 + 10 on Glu-D1, and Xiaoyan 6 and Yumai 7 carry the 14 + 15 on Glu-B1. Four varieties, Funo, Nongda 139, Zhengzhou 683 and Fan 6 convey the 17 + 18 on Glu-B1. The 18 bread wheat varieties recommended by the Ministry of Agriculture in 1992 could be classified into two groups, 5 + 10 and 14 + 15. Zhongzuo 8131 and its selections are the typical genotype of 5 + 10. Genes coding the two subunits are from either Yecora F-70 or IRN68-181. Xiaoyan 6 and its derivative varieties are the typical genotype of 14 + 15. The genes coding 17 + 18 subunits in Chinese varieties were derived from Funo or its selections. These results basically reflect allelic changes on Glu-1 in Chinese wheatvarieties in the past 50 years. It is also proven that HMW-GS components may have great diversity betweenlines from the same cross, which causes great difference on baking quality.     

小麦新品种川农16与新材料H461贮藏蛋白及SSR差异分析

应用酸性聚丙烯酰胺凝胶电泳(A-PAGE)、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)和简单重复序列(simple sequence repeat,SSR)标记,对穗数型多分蘖小麦品种川农16与大穗型寡分蘖小麦品系H461生化及分子水平上的遗传差异进行了检测.结果表明,川农16与H461间至少有10条醇溶蛋白差异带,其高分子量谷蛋白亚基组成分别为(1,20,5 10)和(2*,7 8,2 12).在小麦21条染色体上的72个SSR位点上共检测到95个等位变异,每一个位点所检测到的等位变异数目为1至2个,平均1.3个;其中,23对SSR引物(31.9%)能够揭示川农16与H461间的差异.     

Genetic variation of the durum wheat landrace Haurani from different agro-ecological regions

The durum wheat landrace Haurani (Triticum durum Desf.) is grown under contrasting climatic regions of Syria from Deir Ezzor, in the North-East (230 m altitude, 150 mm mean annual rainfall), to Qunaytra, in the South-West (1060 m altitude, 825 mm mean annual rainfall). In order to assess the genetic variation between and within Haurani populations, samples from eight provinces of Syria (Daraa, Damascus, Qunaytra, Deir Ezzor, Hassakeh, Aleppo, Homs and Hama) were analysed by RFLPs and seed storage proteins of glutenin subunits as markers. The analyses showed the presence of genetic polymorphisms in all populations with the highest values in those from Homs and Hassakeh. Moreover, the results point out differences in genetic distances between populations; some populations were further apart, such as Damascus and Aleppo, whereas others were closer to each other, for instance Homs and Hama. Cluster analysis identified two distinct groups of populations, characterized by geographical proximity, with similar rainfall and altitude. It is suggested that the similarity of landraces at locations close to each other might be the result of more frequent seed exchanges between farmers or of gene flow due to 5% estimated outcross rate of Haurani.     

Impact of ethanol,succinic acid,and the combination thereof at levels produced during sponge fermentation on hard wheat,soft wheat,and durum wheat farinograph rheology

The sponge and dough mixing process is one of the most common in the world, yet the mechanistic understanding of this process has yet to be sufficiently explored. In this study, aqueous solutions of ethanol, succinic acid, and their combination were prepared at concentrations intended to replicate fermentation times of 3, 4 and 6 h. These solutions were added to a farinograph mixer to make dough using hard wheat, soft wheat, and durum wheat flour. The results indicate that these yeast metabolites (ethanol, succinic acid) impact the mixing resistance, peak mixing value, and dough mixing stability in each of the flour types, likely primarily affected by the ratios of gliadin to glutenin and LMW glutenin in each flour type. Results suggest a stabilizing non-covalent interaction imparted by gliadin at peak mixing time, a stabilizing effect of HMW glutenin during break down, and synergistic effects of ethanol and succinic acid that leads to a faster rate of breakdown in later stages of mixing. It also suggests an increase in mixing resistance when acidulants are added to durum wheat dough. Taken together, this study adds new insights on the sponge and dough mixing process in a way that has not previously been conducted.